A handler for testing semiconductor devices (hereinafter, “handler”) is an equipment configured to electrically connect semiconductor devices fabricated with the scheduled manufacturing process to a tester and to classify the semiconductor devices according to the result of test.
A handler used for testing semiconductor devices is disclosed in various patent documents, such as Japanese Patent Laid-open Publication No. 2011-242149 (hereinafter, “the related art”).
In the proposed related art technology, the semiconductor devices are fed or recovered to and from the test sockets (in the related art, named by “sockets for inspection”), using the device feeders (in the related art, named by “heads for inspection”).
The test may be carried out in a way of electrically connecting the semiconductor devices fed into the test sockets by the device feeders to the tester. The semiconductor devices finished in testing may be recovered from the test sockets by the device feeders. At this moment, it may occur that a semiconductor device finished in testing may not be recovered from the test socket due to malfunction of the related components and may remain in the test socket. In this case, when a new semiconductor device is fed into the test socket by the device feeder, the remaining semiconductor device, the new semiconductor device or the test socket may be damaged.
To prevent such a case, the related art uses a method for determining whether a semiconductor device finished in testing remains in a way of taking a photograph of the test socket using a fourth photographing apparatus and analyzing data of the photograph.
Meanwhile, a handler in these days includes a pair of device feeders which feeds and recovers the semiconductor devices to and from the test sockets alternately, thereby achieving higher rate of processing. Hereinafter, such a method for feeding and recovering the semiconductor devices will be described in detail with reference to FIG. 1 and FIGS. 2A and 2B.
A pair of device feeders 141, 142 while reciprocating in the forward and backward direction (see arrow) feeds the semiconductor devices (D) to the test sockets 171 or recovers the semiconductor devices from the test sockets 171. For example, in case where eight test sockets 171 are arranged with a 4×2 matrix form in the socket plate 170, each of the pair of device feeders 141, 142 has eight pickers (P) with a 4×2 matrix form in order to grip or release gripping eight semiconductor devices.
In the handler having the above configuration, for example, in case where as remarked by (W), the first device feeder 141 positioned in the upper portion of the socket plate 170 recovers the semiconductor devices (D) from the test sockets 171, in the state shown in FIG. 2A, the second device feeder 142 may be positioned in the upper portion of the socket plate 170 as the pair of device feeders 141, 142 continues to move forward together, as the state shown in FIG. 2B.
In the state shown in FIG. 2B, the semiconductor devices (D) are fed to the test sockets 171 by the second device feeder 142, as remarked by (S), and then test thereof is initiated. At this moment, the first device feeder 141 puts down the semiconductor devices (D) finished in testing on one side of the first pocket table 111a and then grips the semiconductor devices (D) to be tested from the other side of the first pocket table 111a. 
For such an operation, the first pocket table 111a is configured to move in the left and right directions. When the semiconductor devices (D) fed into the test sockets 171 by the second device feeder 142 are finished in testing, the second device feeder 142 recovers the semiconductor devices (D) finished in testing from the test sockets 171. At this moment, the second device feeder 142 moves backward together with the pair of device feeders 141, 142, and thereby the first device feeder 141 becomes to be positioned in the upper portion of the socket plate 170, as the state shown in FIG. 2A. Likewise, in the state shown in FIG. 2A, the first device feeder 141 feeds the semiconductor devices (D) to the test sockets 171. Next, the second device feeder 142 puts down the semiconductor devices (D) finished in testing on the second pocket table 112a, and grips new semiconductor devices (D) to be tested.
As described above, the semiconductor devices (D) are fed or recovered alternatively using the pair of device feeders 141, 142, thereby improving a processing efficiency.
However, it is difficult for a camera to take a photograph of the plane of the test socket 171 because the pair of device feeders 141, 142 is positioned in the upper portion of the test socket 171 alternatively and also moves on the test socket 171.
The camera may be configured to take a photograph of the test sockets 171 under the stationary state after the pair of device feeders 141, 142 is deviated from the upper portion of the socket plate 170 in order to solve such a difficulty, which however results in lower processing efficiency.